docs: def _gam(self):
          """ Lorentz factor array
          """
          log10gmin = np.log10(self.Eemin / mec2).value
          log10gmax = np.log10(self.Eemax / mec2).value
          return np.logspace(
              log10gmin, log10gmax, int(self.nEed * (log10gmax - log10gmin))
          )